The overall goal for the proposed research is to develop and validate a nuclear magnetic resonance (NMR) zeugmatographic system to monitor myocardial ischemia in time and space. The characteristics of the system are to include a high degree of sensitivity and specificity for myocardial ischemia, a spatial resolution of approximately one centimeter, the capability for sequential use in the human, and a measurement time of short enough duration to detect transient events. The isolated, perfused rat heart will be the experimental model. The sensitivity and specificity of T1, longitudinal relaxation time, for myocardial ischemia will be established through correlation with biochemical markers of ischemia. The proton NMR imaging system will utilize the "sensitive point technique" which provides for obtaining separated signals from identifiable areas of the myocardium in a short time period. Evaluation of the imaging system will initially be approached through comparisons with microsphere distribution. Alternative validation techniques will be sought and developed as required.